1. Field
The following description relates to a touch screen, more particularly, to a touch screen panel and a method for manufacturing the touch screen panel.
2. Description of Related Art
Touch screens may be classified into electrostatic capacitive type touch screens, resistive overlay type touch screens, infrared ray (IR) type touch screens, and surface acoustic wave (SAW) type touch screens.
In a resistive overlay (constant pressure) type touch screen, a touched position is recognized based on the electric signals generated as transparent electrodes of a upper substrate and lower substrate contacts each other when a finger or pen touches the substrates. Resistive overlay type touch screens are inexpensive, and are favorable for miniaturization since they are highly accurate. Thus, resistive overlay type touch screens may be mainly adopted for usage in personal digital assistants (PDAs), portable multimedia players (PMPs), navigations, and handsets and the like.
In an electrostatic capacitive type touch screen, when an electric conductor touches a transparent electrode on a substrate, for example by a finger touching the transparent electrode on the substrate, a constant electrostatic capacitive layer will be formed on an insulation layer, through which signals are transmitted. The touched position can then be recognized by calculating the size of the transmitted signals and detecting the position accordingly.
Although resistive overlay touch screens are favorable in terms of cost, and electrostatic capacitive type touch screens cost more that resistive overlay type touch screens, electrostatic capacitive type touch screens are more preferred by users due to their high light transmission index, multi-touch capability, and high reaction speed. Hence, electrostatic capacitive type touch screens are expected to become the mainstream in portable terminal touch panels in the years to come.
A surface acoustic wave (SAW) type touch screen recognizes a touched position by sensing the reduction in wave size as the surface acoustic wave discharged meets an obstacle. Surface acoustic wave type touch screens have high light transmission index, accuracy and definition, and thus they are mostly applied to unmanned information terminals installed in outdoor places. They are applicable to large sized panels, but are susceptible to contamination of sensors and liquid.
Infrared ray (IR) type touch screens use the characteristic of infrared ray which is not visible to humans but goes straight and thus gets blocked when it meets an obstacle. This type of touch screen may be made by just one sheet of glass without the need of depositing an indium tin oxide (ITO) film or glass plate on a front surface of a display, and thus it is a method providing the highest transmission index.
The electrostatic capacitive type TSP (touch screen panel) is the only type of touch screen which enables multi-touching that is the basis for emotional touching and where high transmission sensors can be provided therein. Large area slim touch sensor technique providing the emotional touch function applicable to large area displays is expected to be the center of touch sensor technique within the next 10 years.